Two Marks Question and Answers

TWO MARKS QUESTION AND ANSWERS

EMBEDDED SYSTEM

1. Define Embedded Systems.

An embedded system is one that has computer hardware with software embedded on it as one of

its most important component. An embedded system is a computing device that does a specific

and repetitive job.

2. Write some applications of Embedded Systems.

 Smart card

 Missiles & Satellites

 Computer Networking

 Automotive s

3. What are the classifications of Embedded system?

 Small scale Embedded System

 Medium scale Embedded System

 Sophisticated Embedded System.

4. Give examples for Small, Medium & sophisticated scale embedded systems.

Small Scale Embedded System

 Automatic chocolate vending machine

 Stepper motor controller for a robotics system

 Washing or cooking system

 Multitasking toys

Medium Scale Embedded System

 Computer Networking Systems

 Entertainment systems

 Embedded firewall / Router

 Signal tracking system

Sophisticated Scale Embedded System

 Embedded system s for wireless LAN & for convergent technologydevices.

 Security products & high speed network security, gigabit rate encryption rate products

 Embedded system for real time video & speech

5. List the categories of embedded system.

 Stand-alone embedded systems. Eg. AC, Oven, CD player, TV.

 Real-time systems. Eg. Aircraft control, Missile & Satellite control

 Networked Information appliances. Eg. Weather monitoring system

 Mobile Devices. Eg. PDAs, Smart phones.

6. List the specialties of embedded systems.

 Reliability Performance

 Power Consumption Cost

 Size Limited User interface

 Software upgradation capability

7. List the factors to be considered while evaluating the processor for embedded system.

 Clock Speed

 Length of Registers

 Number of Registers

 Width of Data and Address bus

 Internal RAM & ROM

 Interrupt lines

 No. of programmable I/O lines

 On-chip peripherals such as Timers, UART, ADC, DAC, etc.

8. What are the hardware components of embedded systems?

 Input devices, Interfacing/Driver circuits,

 Processor

 Timer s

 Interrupt Controller

 Memory

 Serial/Parallel Ports

 Output Interfacing/Driver circuits

 Power supply,

 Reset & Oscillator circuits.

9. Define processor.

A processor is a Chip, which implements a process or processes as per the command given to it.

10. Define Watch Dog Timer

Timing device that resets the system after predefined Time outfit is activated with in few clock

Cycles after the Power up.

11. Compare CISC and RISC processor.

CISC:Complex Instruction Set Computer (CISC)

Aim of designing CISC processor is to reduce the softwarecomplexity by increasing the

complexity of the processorarchitecture. CISC has large no of instructions. Instructionsrequiredto do a job is less and hence, the memoryrequirement in less. No. ofregisters are available inCISCprocessor is very less. Eg. Intel x86 family and Motorola 68000 series processors.

RISC:

Reduced Instruction Set Computer (RISC)RISC has limited no. of instructions and hence,

complexoperation is carried out through sequence of more simpleinstructions. Large number ofregisters is required in RISCprocessor. Another important feature of RISC processor ispipelinedinstruction execution.Embedded systems generally use RISC processor.

Eg. ARM, ATMEL, AVR, MIPS, Microchip’s PIC family processors,Power PC and Sun

SPARC processor.

12. What are the processor architectures in embedded systems?

Von-Neuman Architecture: This architecture has common memory for both data and program

codes.

Harvard Architecture: This architecture has separate memory for data and program codes.

13. What is microcontroller?

A microcontroller is a unit with a processor. It is a single chip VLSI unitwhich, thought having

limited computational capabilities, possesses enhanced input-output capabilities and a number of

on-chip functionalunits.

14. What are the functional circuits of a microcontroller?

The functional circuits of a microcontroller are,

 Processor

 Data & stack in internal RAM

 Timers & Watchdog timer

 ROM / PROM / EPROM

 External Memories Interfaces

 Interrupt Controller

 I/O Ports Control & Interfaces / Drivers

 Serial UART communication port

15. What are the features of DSP?

A DSP provides fast, discrete-time, signal processing instructions. It hasvery large instruction word (VLIW) processing capabilities, it processesSingle Instruction Multiple Data (SIMD) instructions fast, and it processesDiscrete Cosine Transformations (DCTs) and inverse DCTs (IDTs) fast.

16. What is GPP & ASIP?

GPP: A processor from a number of families of processors, microcontroller,embedded

processors and DSPs having a general purpose instruction setand readily available compilers toenable programming in a high level language is called a General Purpose Processor (GPP).

ASIP: A processor designed for specific application on a VLSI chip is calledan Application

Specific Instruction Processor.

17. What is ASSP?

Application Specific System Processor is a processing unit for specifictasks, for e.g. Image

compression and that is integrated through thebuses with the main processor in an embeddedsystem.

18. What is System-On-Chip?

A system on a VLSI chip that has all of needed analog as well as digitalcircuits. For example,mobile phone.

19. What are the various forms of system memories?

 Internal RAM

 Internal ROM / PROM /EPROM

 External RAM

 Internal & External Caches

 External ROM / PROM

 RAM Memory buffers

 Hybrid memory such as E2PROM, NV-RAM or flash memory

21. List the important types of Displays.

 Light Emitting Diode (LED) Liquid Crystal Display (LCD)

 Thin Film Transistor (TFT) Display Organic Light Emitting Diode (OLED)

22. List the important Serial communication protocols.

 Inter-integrated Circuit (I2C)

 Serial Peripheral Interface (SPI)

 Universal Serial Bus (USB)

 Controller Area Network (CAN)

23. List the important communication interfaces used in embedded systems.

 Serial interface using RS232

 Serial interface using RS422/RS485

 Universal Serial Bus (USB)

 Infrared

 Ethernet

 Wireless interface using IEEE 802.11 (WLAN)

 Bluetooth

 ZigBee IEEE 802.15.4

24. Define interrupt handler.

It is a unit that handles the processor operations arising out of an interrupt from a source.

25. What is watchdog timer?

It is a timer that timeout from which resets the processor in case the program gets struck for anunexpected time.

26. What is reset circuit and power-up reset?

The reset circuit activates for a fixed period and then deactivates. It helpsthe processor to startthe processing of instructions from a startingaddress.Power-up reset vector also provides astarting address which is differentfrom that provided by a reset circuit.

27. What are the steps required for converting assembly language intoa ROM image?

 Assembler

 Linker

 Loa d e r

Locator & Device Programmer

28. What is ROM image?

The final stage software is also called ROM image, because just as animage is a unique sequenceand arrangement of pixels, embeddedsoftware is also a unique placement and arrangement ofbytes forinstructions and data.

29 . What is the use of code optimizer?

Code optimizer is used in the conversion of high level language into a ROMimage for optimizingthe code before linking.

30 What is Compiler?

Compiler is a software tool that converts a high level program (writtenusing programming

languages like C, C++, Java, and so on) into an objectcode.

31 What is Assembler?

Assembler is a software tool that converts an assembly program (writtenusing mnemonics of aprocessor, i.e., instruction set of a specificprocessor) into an object code.

32 What is Timer and counting devices?

A Timer gets the inputs from the internal clock of a processor or from system clock and

generates a required time delay.

Counting device is a unit for getting the count-inputs on the occurrence of events that may be atirregular intervals.

33 What are the types of Timer?

There are two types of timer. They are,

 Hardware timer

 Software timer

34 What are the different states in a timer?

The different states in a timer are,

 Reset State

 Idle State

 Present State

 Overflow State

 Active or Blocked State

 Done State

35 Is it necessary to have a hardware timer device in a system? How does it work?

Yes, it is necessary to have atleast one hardware timer device in a system. It is used as a systemclock. The hardware timer gets the input from a clock out signal from the processor and activatesthe system clock as per the num ticks preset at the hardware timer

36 Mention the types of data Transfer in USB Bus

Controlled Data Transfer, Bulk data Transfer, Interrupt driven data Transfer, IsosynchronousTransfer.

37 what is Real Time Clock?

RTC is aclock that causes Occurance of Regular intervals of interrupt on its each Ticks.Timingdevice once started never resets .It is used in System to save Current time & Date.

38 Give the Classification of Serial & Parallel port of IO devices.

Synchronous Serial Input

Synchronous Serial Output

Asynchronous Serial UART Input

Asynchronous Serial UART Output

Parallel Port one bit Input

Parallel One bit output

Parallel Port Input

Parallel Port Output

39 Compare Synchronous & A Synchronous communication

In Synchronous Communication a Byte or Frame is Received or Transmitted at Constant Timeinterval with Uniform Phase difference .data is Sent at Fixed Time interval. Eg Frames sent overLAN .

In A Synchronous Communication a Byte or Frame is Received or Transmitted at variableTimeinterval .Eg RS 232 Communication between two UART devices.

40 List the Parallel communicating Buses.

ISA ,PCI( Peripheral Component Interconnect ), ARM

42 Mention the processor Features in Embedded System

It should Operate at high clock Speed

Provide High computing performance with Pipelinning & SuperScalar Architecture

Provide Fast Context Switching in Multitasking System.

43 what is DMA controller?

It Facilities a multi byte data transfer or Block of data transfer between the External device &System.

Modes of Operation:

Single Transfer at time & then release IO bus hold on the system bus after each transfer

Burst transfer at time & release of IO bus hold on the System Bus.

Bulk transfer & then release of IO bus hold on the System Bus after the Transaction is

Completed.

44 what is Device driver ?

Device driver is a program that controls a particular type of device that is attached to your

computer. There are device drivers for printers, displays, CD-ROM readers, diskette drives, and

So on. A device driver essentially converts the more general input/output instructions of the

Operating system to messages that the device type can understand. Virtual device drivers handle

software interrupts from the system rather than hardware interrupts. Virtual device driver for

each main hardware device in the system, including the hard disk drive controller, keyboard, and

serial and parallel ports are used to maintain the status of a hardware device that has changeable

settings.

45 what are the Serial Communicating Protocol?

I^2 C Bus, CAN Bus, USB Bus.

46 Give Memory allocation Schemes in a system

Static Memory Allocation : Allocated during Compile Time… Entire space in memory is

Allocated.

Dynamic Memory Allocation : Allocated during Run Time….. Blocks of Memory will be

allocated.

47 what are the features of USB?

It can be Plugged , Configured & used, reset & Reconfigured it can Share Bandwidth with otherdevices,detached & Reattached. Attaching & detaching can be done without Rebooting.it can be

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